1. Field of the Invention
The present invention relates to a process for producing metallic chromium plates and sheets (hereinafter called "sheets") from metallic chromium powders, which process comprises rolling (or compacting) metallic chromium powders having -200 to -400 mesh particle size, sintering, re-rolling and annealing.
2. Description of the Prior Art
Conventionally, no trials or practices have been made for forming metallic chromium powders into shaped products such as sheets, because metallic chromium ingots are very brittle. However, metallic chromium has inherently very excellent properties, such as high strength at high temperatures, high resistance to various acids and high corrosion resistance, and is much less precious as compared with alloying elements, such as nickel and cobalt, which are added for desired heat resistance. Therefore, metallic chromium has very wide and extensive potential applications as alloying element for giving alloys heat resistance and corrosion resistance or as basic component of heat resistance or corrosion resistant alloys. On the other hand, metallic chromium has an inherent disadvantage that it is generally brittle and hence has great difficulty in performing plastic working so that the actual applications of metallic chromium have been largely limited. Therefore, strong demands have been being made for improving the brittleness and workability of metallic chromium.
Under the situation as mentioned above, if metallic chromium sheets can be efficiently and advantageously produced, various wide applications will be developed for such metallic chromium sheets due to their inherent excellent properties.
Various extensive studies and experiments have been made by the present inventors for improving the brittleness and poor workability peculiar to metallic chromium and have discovered a process for producing shaped products directly from metallic chromium powders, and the present invention has been completed on the basis of this discovery.